Researchers at the University of Tokyo’s School of Medicine have shown for the first time that caffeine intake can significantly increase the eye’s ability to produce tears, a finding that could improve treatment of dry eye syndrome. This common eye condition affects about four million people age 50 and older in the United States. For many, dry eye syndrome is simply uncomfortable and annoying, but for others it escalates into a vision-threatening disease. All of the 78 participants in the new study produced significantly more tears after consuming caffeine than after taking a placebo. The study is available in Ophthalmology, the journal of the American Academy of Ophthalmology.